The invention relates generally to insecticides and more particularly to a topical insecticide, such as one suitable to use on house pets such as cats and dogs.
The infestation of animals with fleas, ticks, flies and the like is highly undesirable. Accordingly, it has become common to administer both topical and internal insecticides to livestock and pets. Topical applications can be desirable, in that many insecticides are acceptably safe when used topically, but not when used internally.
Various topical insecticides have drawbacks. Some require a large volume to be applied to the animal. This can cause considerable mess and can lead to an unpleasant smell. Also, when the animal is a house pet, there is a further complication in that the insecticide should be safe for human contact. It should also not lead to staining of furniture, carpeting and the like. Finally, even if safe, topical insecticides for house pets should not be irritating or lead to rashes, hair loss or exhibit other unpleasant side effects.
Accordingly, it is desirable to provide an improved topical insecticide, which overcomes drawbacks of the prior art.
Generally speaking, in accordance with the invention, a topical insecticide is provided which can be safe to use and avoids many common deleterious side effects of conventional topical insecticides. In one preferred embodiment of the invention, the active ingredient of the insecticide formulation is an amine derivative, having a nitro-methylene group, a nitroamino group or a cyanoamino group, which can be formulated to have low toxicity and excellent insecticidal activity. Active ingredients of insecticides and their method of formation in accordance with the preferred embodiments of the invention are discussed in U.S. Pat. Nos. 5,532,365 and 5,434,181, the contents of which are incorporated herein by reference. One particularly suitable insecticide is 1-{(tetrahydro-3-furanyl)methyl}-2-nitro-3-methylguanidine (dinotefuran). Dinotefuran is an aldulticide that will kill adult fleas.
In one preferred embodiment of the invention, the active portion of the insecticide formulation comprises (tetrahydro-3-furanyl)methylamine derivatives of following formula (1). 
Active ingredients and insecticides in accordance with preferred embodiments of the invention are generally available as crystals and solids. Therefore, they need to be dissolved or otherwise put into a liquid form for use as topical spot products on animals.
In one aspect of the current invention, the compound is dissolved in solvent to a concentration range of 2-15%, more preferably 4-9% and most preferably about 5 to 8%, with 6% as a preferred example. All percentages, unless otherwise evident, are on a weight basis.
In one embodiment of the invention, the preferred solvent component comprises a mixture comprising water and an alcohol, preferably ethanol, at a concentration range of 50-80% ethanol, more preferably 65-75% ethanol and most preferably about 69-71% ethanol, with a preferred example 70% ethanol. The remainder can be water. The insecticide formulation can include various additions to the ethanol/water combination.
In another embodiment of the invention, the preferred solvent component comprises a mixture comprising water, ethanol and isopropanol, wherein the final concentration of total alcohol range from 50-80% alcohol, more preferably 65-75% alcohol and most preferably about 69-71% alcohol, with a preferred example 70% alcohol. The remainder can be water. The concentration of ethanol and isopropanol are 25-45% ethanol, 25-45% isopropanol, more preferably 30-40% ethanol, 30-40% isopropanol and most preferably 35% ethanol and 35% isopropanol.
In another embodiment of the invention, the preferred solvent comprises a mixture comprising dipropyleneglycol monomethyl ether (DPM) and water at a concentration range of about 30-70% DPM, more preferably about 45-55% DPM and most preferably about 50% DPM/50% water mixture.
In yet another embodiment of the invention, the preferred solvent is a mixture comprising water, ethanol and DPM at a concentration range of 25-40% ethanol, 25-40% DPM, more preferably 30-35% ethanol, 30-35% DPM and most preferably equal volumes of each component (i.e., 33% ethanol, 33% DPM and 33% water).
Accordingly, it is an object of the invention to provide an improved topical insecticide, which overcomes drawbacks of the prior art.